Electrodynamic transducer and use thereof in loudspeakers and geophones
US8111870B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Nov 2, 2006 |
| Grant date | Feb 7, 2012 |
| Priority date | — |
| Expiry date | Jan 23, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2209/022
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An electrodynamic transducer includes a frame and contains at least one electric coil which is placed in a static magnetic field and which can move about a rest position in a vertical free space. The coil(s) is wound around and fixed to a mandrel and a return member is used to return the coil-bearing mandrel to the rest position in the absence of an external bias, the straight cylinder defining an inner volume and an outer volume. The magnetic field is produced by outer and inner magnetic structures which each comprise at least one fixed permanent magnet in the form of a ring. The motor does not contain any ferromagnetic or magnetic part between the outer volume and the inner volume. At least the part of the frame that is used to fix the magnets is made from a non-ferromagnetic and non-magnetic material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.